The "Telephone Operating System in the Vatican" is 95 Years Old, Vatican Moved to GNU/Linux
According to this old photo:
This morning: Phone Adoption Very Low in Vatican, Windows Usage Fell Nonetheless
Forget about TempleOS. Apparently the Vatican runs GNU/Linux. This page is still available in the Wayback Machine.
"In 1993," they said, "when the retroactive catalogue of the Vatican Library was begun, the UNIX operating system was adopted [...] In addition, 27 servers form the Power Core of the IT Center, of which 7 are in a UNIX AIX environment, 19 in a Linux SUSE and Red Hat environment, and 3 in a Microsoft environment (virtualized on Linux systems with VMWare)."
Microsoft had only 3 out of 27 servers. That was a long time ago. Maybe Microsoft is down to zero already. █